The present invention relates to a machine for making crushed iced drinks also known as "Sicilian style" crushed ice drinks.
There are various types or "classes" of machine for making crushed ice drinks, and for example there are machines which comprise a refrigerated tank, within which a stirrer rotates, or else there are machines which comprise a tank with vertical axis, within which is housed a cylinder, likewise with vertical axis, internally housing the evaporator of a refrigerator unit, cooperating with means for stirring the surrounding liquid to be frozen, or there are also machines fitted with a freezing chamber with horizontal axis. The subject of the present invention is a machine of this last type.
In the field of so-called horizontal crushed ice drinks makers, machines for making crushed ice drinks are known which comprise a metal freezing cylinder with horizontal axis in a relationship of heat exchange with the evaporator of a refrigerator circuit, internally housing means for stirring the mixture for the preparation of the frozen crushed ice drink. However, such machines have disadvantages from the maintenance point of view, in so far as the inside of the freezing cylinder can only be reached by opening the front door of the machine on which the dispensing tap is mounted, and also have disadvantages of an aesthetic/commercial nature, in so far as the consumer cannot observe the contents of the machine during the phases of operation.
Machines for making crushed ice drinks are known which comprise a transparent tank with horizontal axis, provided at one end with a dispensing tap, and within which is housed a refrigerating element consisting of a metal cylinder closed at both ends, and internally housing the evaporator of a refrigerator unit. This cylinder also is arranged in the tank with its axis horizontal. Right around the said cylinder is arranged a motor-driven screw which rotates so as continuously to push the product towards the end of the tank bearing the dispensing tap.
U.S. Pat. No. 4,900,158 describes a machine for making crushed ice drinks comprising a transparent tank, preferably made of plastic, provided at one end with a tap for dispensing the frozen product, and internally housing a refrigerating element consisting of a hollow metal cylinder with double-walled shell housing the evaporator of a refrigerator unit in the gap between the two walls. In the axial cavity of this cylinder is housed a first screw, while its outer shell is surrounded by a second screw, and these two screws are driven in opposite directions by a motor, so as to transport the mixture to be frozen in a continuous motion from one end of the cylinder to the other through its axial cavity and along its outer shell.
Machines designed in this way have numerous advantages as compared with the state of the art and, in the machine according to U.S. Pat. No. 4,900,158 for example, there is undoubtedly better utilization of the cold generated by the evaporator, as compared with the other machines examined earlier. However, both the machine according to the cited U.S. Patent and the other known machines with freezing cylinder with horizontal axis have some drawbacks. This is because, not infrequently in machines of this type, accumulations of product may occur in proximity to the delivery end of the tank of the machine. Moreover, the outlet thrust exerted on the product may not be entirely effective and such as to ensure regular delivery through the dispensing tap placed at the head of the machine.
To remedy these and other drawbacks, the present invention provides a machine for making crushed ice drinks which comprises stirrer means able to avoid the accumulation of product at the head end of the machine and which moreover provide an adequate thrust on the product as it comes out of the dispensing means.
The subject of the present invention is therefore a machine for making crushed ice drinks comprising a tank with horizontal axis provided at one end with means for dispensing the iced product, and internally housing a refrigerating element consisting of a hollow metal cylinder with double-walled shell housing the evaporator of a refrigerator unit in the gap between the two walls. A screw is housed in the axial cavity of the said cylinder, while its outer shell is surrounded by a stirrer/scraper element consisting of one or more radial ribs or fins parallel to the directrices of the cylinder a series of blades able to exert a positive axial thrust on the product to be delivered towards the said dispensing means also being provided at that end of the said stirrer device facing the dispensing means of said tank. Advantageously, the said scraper ribs or fins and the said blades are connected together.
Advantageously the outer stirrer means act concurrently as elements for scraping the outer shell of the freezing cylinder. Alternatively, it is possible to provide means for scraping the outer surface of the refrigerating element which are separate from the stirrer elements.
In one embodiment of the invention, the said blades are mounted at the free end of radial arms which depart from a hub for connection to the screw, the stirrer fins being connected to the same end of said arms.
In a further embodiment, the said scraper means are provided on the inner edge of the stirrer fins, said fins being provided with support bars which are connected at one end to the said radial arms and which bear, in proximity to the opposite end, a ring which contributes to the stiffening of the structure.
In another embodiment of the invention, the said scraper means are mounted separately from the said fins and are sandwiched between two rods welded at one end to one of the said radial arms, and at the other end to the said ring. In this case, the said ring no longer merely fulfils the function of structural stiffening, but also that of supporting the outer stirrer means which are ill-balanced; such support is obtained by resting the said ring on a circular support element integral with the said tank.
One of the stirrer fins can be substituted by an oscillating vane hinged to a bar connected to one of the said radial arms and to the said ring.